Preparation of tertiary alkyl isocyanates

Abstract

A process for the production of tertiary alkyl isocyanates, such as tetramethylxylylene diisocyanates, is disclosed in which the corresponding tertiary alkyl halide is reacted with an alkali metal cyanate utilizing a zinc-pyridine complex as a catalyst which has been prereacted with the cyanate before reaction with the halide.

I claim: 
     
       1. A process for production of a tertiary alkyl isocyanate from the corresponding tertiary alkyl halide which comprises: a. preparing a complex of a zinc salt of an acid selected from mineral acids and carboxylic acids and pyridine in a 1:2 mole ratio,   b. thereafter reacting said zinc-pyridine complex with an alkali metal cyanate to form a zinc-pyridine-cyanate complex containing 2 equivalents of cyanate anion per atom of zinc, and   c. reacting said zinc-pyridine-cyanate complex with said tertiary alkyl halide in an aprotic solvent at a temperature of from 0° C. to 100° C. to form said tertiary alkyl isocyanate.   
     
     
       2. A process according to claim 1 in which said zinc salt is zinc chloride. 
     
     
       3. A process according to claim 2 in which said solvent is methylene dichloride. 
     
     
       4. A process according to claim 2 in which said halide is a di(2-chloroisopropyl)benzene dichloride. 
     
     
       5. A process according to claim 2 in which said halide is an α,α-dimethyl-isopropenyl benzyl chloride. 
     
     
       6. A process according to claim 2 in which said halide is a tris(2-chloroisopropyl)benzene. 
     
     
       7. A process according to claim 2 in which said halide is a di(2-chlorisopropyl)naphthalene. 
     
     
       8. A process according to claim 2 in which said halide is α,α-dimethylbenzyl chloride.